Electrochemical Determination of Dopamine, Acetaminophen and Tryptophan using AuPdCu-rGO-MWCNTs Nanocomposite as the Sensing Layer

In this study, AuPdCu-rGO-MWCNTs nanocomposite was synthesised by a chemical reduction method which was applied to fabricate an electrochemical sensor for simultaneous determination Dopamine (DA), Acetaminophen (AC) and Tryptophan (Trp) by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. The formation of Au, Pd, and Cu nanoparticles on rGO-MWCNTs nanocomposite are characterized by XRD, FTIR, and SEM techniques. The relationship between the concentration of DA, AC, and Trp with the response of AuPdCu-rGO-MWCNTs/CPE was linear in the range of 10 nM to 8.3 μM, 20 nM to 12.5 μM and 10 nM to 9.4 μM by DPV technique, and 0.007-8.0, 0.011-11.6 and 0.008-8.8 μM by amperometric method, respectively. Also, the detection limits for DA, AC, and Trp were calculated to be 3, 7 and 4 nM, respectively by the voltammetric method and 2, 5 and 3 nM for DA, AC and Trp, by amperometric method. The investigations show that AuPdCu-rGO-MWCNTs/CPE has acceptable selectivity, stability, repeatability, and reproducibility. Finally, AuPdCu-rGO-MWCNTs/CPE was successfully applied to determine the analytes in the urine, blood plasma, and AC Tablet by desirable percentage of relative standard deviation and recovery.